1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Hypervisor filesystem for Linux on s390
4 *
5 * Diag 0C implementation
6 *
7 * Copyright IBM Corp. 2014
8 */
9
10#include <linux/slab.h>
11#include <linux/cpu.h>
12#include <asm/diag.h>
13#include <asm/hypfs.h>
14#include "hypfs.h"
15
16#define DBFS_D0C_HDR_VERSION 0
17
18/*
19 * Get hypfs_diag0c_entry from CPU vector and store diag0c data
20 */
21static void diag0c_fn(void *data)
22{
23	diag0c(((void **)data)[smp_processor_id()]);
24}
25
26/*
27 * Allocate buffer and store diag 0c data
28 */
29static void *diag0c_store(unsigned int *count)
30{
31	struct hypfs_diag0c_data *diag0c_data;
32	unsigned int cpu_count, cpu, i;
33	void **cpu_vec;
34
35	cpus_read_lock();
36	cpu_count = num_online_cpus();
37	cpu_vec = kmalloc_array(num_possible_cpus(), sizeof(*cpu_vec),
38				GFP_KERNEL);
39	if (!cpu_vec)
40		goto fail_unlock_cpus;
41	/* Note: Diag 0c needs 8 byte alignment and real storage */
42	diag0c_data = kzalloc(struct_size(diag0c_data, entry, cpu_count),
43			      GFP_KERNEL | GFP_DMA);
44	if (!diag0c_data)
45		goto fail_kfree_cpu_vec;
46	i = 0;
47	/* Fill CPU vector for each online CPU */
48	for_each_online_cpu(cpu) {
49		diag0c_data->entry[i].cpu = cpu;
50		cpu_vec[cpu] = &diag0c_data->entry[i++];
51	}
52	/* Collect data all CPUs */
53	on_each_cpu(diag0c_fn, cpu_vec, 1);
54	*count = cpu_count;
55	kfree(cpu_vec);
56	cpus_read_unlock();
57	return diag0c_data;
58
59fail_kfree_cpu_vec:
60	kfree(cpu_vec);
61fail_unlock_cpus:
62	cpus_read_unlock();
63	return ERR_PTR(-ENOMEM);
64}
65
66/*
67 * Hypfs DBFS callback: Free diag 0c data
68 */
69static void dbfs_diag0c_free(const void *data)
70{
71	kfree(data);
72}
73
74/*
75 * Hypfs DBFS callback: Create diag 0c data
76 */
77static int dbfs_diag0c_create(void **data, void **data_free_ptr, size_t *size)
78{
79	struct hypfs_diag0c_data *diag0c_data;
80	unsigned int count;
81
82	diag0c_data = diag0c_store(&count);
83	if (IS_ERR(diag0c_data))
84		return PTR_ERR(diag0c_data);
85	memset(&diag0c_data->hdr, 0, sizeof(diag0c_data->hdr));
86	store_tod_clock_ext((union tod_clock *)diag0c_data->hdr.tod_ext);
87	diag0c_data->hdr.len = count * sizeof(struct hypfs_diag0c_entry);
88	diag0c_data->hdr.version = DBFS_D0C_HDR_VERSION;
89	diag0c_data->hdr.count = count;
90	*data = diag0c_data;
91	*data_free_ptr = diag0c_data;
92	*size = diag0c_data->hdr.len + sizeof(struct hypfs_diag0c_hdr);
93	return 0;
94}
95
96/*
97 * Hypfs DBFS file structure
98 */
99static struct hypfs_dbfs_file dbfs_file_0c = {
100	.name		= "diag_0c",
101	.data_create	= dbfs_diag0c_create,
102	.data_free	= dbfs_diag0c_free,
103};
104
105/*
106 * Initialize diag 0c interface for z/VM
107 */
108int __init hypfs_diag0c_init(void)
109{
110	if (!MACHINE_IS_VM)
111		return 0;
112	hypfs_dbfs_create_file(&dbfs_file_0c);
113	return 0;
114}
115
116/*
117 * Shutdown diag 0c interface for z/VM
118 */
119void hypfs_diag0c_exit(void)
120{
121	if (!MACHINE_IS_VM)
122		return;
123	hypfs_dbfs_remove_file(&dbfs_file_0c);
124}
125